“Tuida” is a late antique and medieval fortress. It is situated on the hill “Hissarluka” in the northeastern part of the town of Sliven near to the neighborhood called Novo selo. In the past the area was inhabited by Thracian tribes, ancient Romans, medieval Bulgarians.  Its location uncovers a wonderful view to the south – toward the town, and to the north - toward the National Park „Sinite kamani“ ("The Bluse Stones") and toward the town of Sliven.

The Fortress dates back tо the 4th century and existed until the 13th century.

Today it is renovated and opened to visitors who will have the opportunity to take a first-hand look at restored artefacts such as clothing, instruments and equipment/weaponry.